Add support for tcp

[styfle]

Currently, vgrok assumes http but there are some scenarios where you would want to use tcp only.

We could add a flag like vgrok 3000 --tcp vs vgrok 3000 --http which would be the easiest for backwards compat.

Though we could use a url like vgrok --listen http://127.0.0.1:3000 vs vgrok --listen tcp://127.0.0.1:3000 which would provide more options in the future since it includes proto/host/port and allow a path forward for listening on a specific host.

[styfle]

On second thought, this isn't as easy as I had hoped since Vercel Sandbox doesn't support TCP sockets.

I tried this:

const SANDBOX_PORT = 3000;
const sandbox = await Sandbox.create({
    teamId,
    projectId,
    token,
    runtime: 'node24',
    resources: { vcpus: 1 },
    ports: [SANDBOX_PORT],
    timeout,
  });
  const sandboxUrl = sandbox.domain(SANDBOX_PORT);

  const str = `
const net = require('net');

const server = net.createServer((socket) => {
  console.log('Client connected');

  socket.on('data', (data) => {
    console.log('Received:', data.toString());
    socket.write('Echo: ' + data);
  });

  socket.on('end', () => {
    console.log('Client disconnected');
  });
});

server.listen(${SANDBOX_PORT}, () => {
  console.log('TCP server listening on port', ${SANDBOX_PORT});
});`;

  await sandbox.writeFiles([{content: Buffer.from(str), path: 'server.cjs'}]);

  await sandbox.runCommand({
    cmd: 'node',
    args: ['server.cjs'],
    detached: true,
    stderr: process.stderr,
    stdout: process.stdout,
  });

Then tried connecting to the sandbox with nc but it didn't work.

nc sb-3i4ex0ojyinx.vercel.run 80

This seems like its expected behavior unfortunately.